Author : Chaichan Chalothorn

Summary : Three soybean cultivars namely; Clark 63, UPL-SY 2 and Williams were grown to study their growth performance and physiological responses under controlled subsurface drainage conditions at depths of 15, 30, 45, and 60 cm. The depths of subsurface drainage significantly affected the growth of soybean plants mostly during the vegetative growth and early pod-filling stages. Shoot dry weight and total dry matter production (shoot plus root dry weight) were high under the shallow depth of 15 cm but declined as growth progressed. There were slight differences in dry matter production at the subsurface drainage depths of 30, 45, and 60 cm. The longest root was found at the drainage depth of 45 cm. However, the root dry weight increased under the shallow subsurface drainage conditions.